Motor chain saw



Feb. 13, 1968 K. GUTJAHR 3,368,595

MOTOR CHAIN SAW v Filed March 14, 1966 2 Sheets-Sheet 1 in van for: %r/ g lf k2 4r- Feb. 13, 1968 4 K.'GUTJAHR 3,368,595

MOTOR CHAIN SAW Filed March 14,- 1966 -2 Sheets-Sheet 2 lnven for: 70/'/ @00'@ 4/- United States Patent 3,368,595 MOTOR CHAIN SAW Karl Gutjahr, Wendlingen (Neckar), Germany, assignor to Andreas Stihl Maschinenfahrik, Waiblingen, Neustadt, Germany Filed Mar. 14, 1966, Ser. No. 534,125 Claims priority, application Germany, Mar. 13, 1965, St 18,410 9 Claims. (Cl. 143-32) The present invention relates to a motor chain saw with a guiding rail detachable from the driving unit and intended for a saw chain which passes over a driving pinion keyed to the crank-shaft of the motor and covered by a cover, while a handle structure extending approximately in the direction of the crank-shaft is connected to the motor chain saw.

The driving unit of such motor chain saw is usually employed also for purposes other than driving the saw chain. For instance, the driving unit may be connected to a soil drill, a peeling device for peeling the bark from tree trunks, a free cutting device, and the like. If devices of this type are coupled to a driving unit, the cover covering the driving pinion as well as the handle structure becomes superfluous and may interfere with the operation of the device so that these two structural elements will have to be removed. With heretofore known motor chain saws of the type referred to above, the handlestructure and the cover are so connected to the device that they have to be individually detached from the driving unit which requires considerable time.

It is, therefore an object of the present invention to provide a motor chain saw of the above mentioned general type, which will overcome the drawbacks outlined above.

It is another object of this invention to provide a motor chain saw which will permit a very simple and fast removal of the handle structure and the cover whenever desired.

It is still another object of this invention to provide a chain saw as set forth in the preceding paragraphs, in which the handle structure and the cover can as a unit be withdrawn from the driving unit.

These and other objects and advantages of the invention will appear more clearly from the following specification in connection with the accompanying drawing, in which:

FIG. 1 illustrates a front view of a motor chain saw according to the present invention.

FIG. 1a illustrates a part of FIG. 1 on a larger scale and partly sectioned.

FIG. 2 is an end view as seen in the direction of the arrow A of FIG. 1.

FIG. 3 is a top view of the chain saw shown in FIG. 2 showing the cover in partially withdrawn condition.

A motor chain saw according to the present invention which is provided with a guiding rail detachable from the driving unit and intended for the saw chain which is passed over a driving pinion rotatably connected to the crank-shaft and covered by a cover while a handle structure extends approximately in the direction of the crankshaft, is characterized in conformity with the present invention in that the handle structure is rigidly connected to the cover at two areas and is connected to the motor block by a plug-socket connection. This type of connection makes it possible to detach the handle structure together with the cover from the driving unit without requiring the detachment of special connecting means. Moreover, the three-point support of the handle structure assures a safe and rigid connection of the handle structure with the motor chain saw.

According to a further feature of the present invention,

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the said plug-socket connection of the handle structure is adapted to be assembled and disassembled in the same direction as the cover so that for purposes of detaching the handle structure, it is merely necessary to withdraw the cover along a straight line from the motor.

In conformity with a further development of the present invention, the two ends of the handle structure are connected to the cover preferably by a clamping arrangement, for instance by a clamp embracing the ends of the handle structure. Advantageously, the handle structure has a portion which extends below the driving unit in a direction approximately parallel to the crank-shaft while the end of this part is connected to the cover. The other end of the handle structure extends approximately perpendicular to the crank-shaft and is connected to the top side of the cover. In this connection it is advantageous to provide the plug-socket connection at the lower part of the handle structure because in this instance it will not interfere with any other parts.

According to a still further development of the present invention, the handle structure has connected thereto an arm which protrudes approximately perpendicular thereto. The free end of said arm has a plug fitting into a corresponding socket of the crank housing of the motor. Advantageously, the said arm is connected by means of a clamp to the handle structure so that it can easily be adjusted to the proper length in which the plug connected to said arm will fit into the socket or recess of the crank housing for the motor.

Referring now to the drawing in detail, the motor chain saw illustrated therein comprises primarily a driving unit 1 including a motor block to which is detachably connected a handle structure for guiding a saw 3 driven by the driving unit 1. Saw 3 includes a guiding rail 3a detachably connected to the driving unit 1. Mounted on guiding rail 3a in customary manner is a saw chain 3b one portion of which is passed over a driving pinion 4 which in its turn is keyed to the crankshaft 1' of the driving unit 1.

Pinion 4 as well as a portion of guiding rail 3a are covered by a cover 5 (FIGS. 1 and 3). Cover 5 which in FIG. 3 is shown in partially withdrawn condition may normally be connected to driving unit 1 for instance by screw bolts.

As will be seen from FIGS. 1 to 3, the handle structure 2 extends in a plane approximately parallel to the axis of the driving pinion 4 and is rigidly connected to cover 5 at two connecting areas 6, 7 and is furthermore connected to driving unit 1 or, more specifically, the motor block thereof at a connecting area 8 (FIG. 1) by means of a plug-socket connection. That portion 11 of handle structure 2 which extends below the driving unit 1 has one end connected to a clamp 13 provided on cover 5 while the other end 9 of the handle structure 2 is approximately perpendicular to the axis of driving pinion 4 and extends downwardly while being connected to a clamp 13 of cover 5.

Portion 11 of handle structure 2 which extends below the driving unit 1 has connected thereto an arm 14 by means of a clamp 15. The free end of said arm 14 comprises a plug 16 adapted to engage a corresponding recess or socket 17 in crank housing 1a of the driving unit 1. With the cover 5 illustrated in FIG. 1 and connected to the driving unit 1, plug 16 engages socket 17 so that handle structure 2 is firmly held on the driving unit 1. When cover 5 is withdrawn from the driving unit 1 in the direction of the arrow 18 (FIG. 3), plug 16 detaches itself from the socket 17 so that the handle structure 2 is connected only to cover 5 and together with the latter can be withdrawn from the chain saw.

In view of the connection of plug 16 to handle structure 2 by means of clamp 15, plug 16 can be turned relaa tive to the handle structure 2 and can be adjusted and arrested precisely in its desired position in which it fits into socket 17.

It is, of course, to be understood that the present invention is, by no means, limited to the particular arrangement shown in the drawing but also comprises any modifications within the scope of the appended claims.

What I claim is:

1. A motor chain saw, which comprises: a driving unit including a crank case and a crank-shaft rotatably mounted in said crank case and a driving pinion rotatably connected to said crank-shaft, guiding rail means detachably connected to said driving unit, a saw chain guided by said guiding rail means and drivingly connected to said pinion, cover means detachably connected to said driving unit to cover said pinion toward the outside of said motor chain saw, handle means having two spaced portions thereof firmly connected to said cover means, and ping-socket connecting means detachably connecting said handle means to said driving unit thereby permitting withdrawal of said cover means and said handle means together as a unit from said driving unit.

2. A motor chain saw according to claim 1, in which the axis of said plug-socket connecting means is approximately perpendicular to the plane along which said cover means is detachably connected to said driving unit, thereby permitting engagement and disengagement of said plugsocket connecting means and assembly and disassembly of said cover means with said handle means in one and the same direction.

3. A motor chain saw according to claim 1, which includes clamping means firmly connecting the ends of said handle means to said cover means.

4. A motor chain saw according to claim 1, in which said handle means ha an approximately U-shaped contour with one of the leg ends bent toward the other leg while one end portion of said handle means is approximately parallel to said crank-shaft and extends below said driving unit when the plane defined by the legs of said U-shaped contour is in approximately upright position, the free end of said one end portion being connected to said cover means.

5. A motor chain saw according to claim 4, in which the other end portion of said handle means extends approximately perpendicularly with regard to the longitudinal extension of said crank-shaft.

6. A motor chain saw according to claim 4, in which said plug-socket connecting means is arranged at that side of said driving unit at which said one end portion of said handle means is located when said handle means is connected to said driving unit.

7. A motor chain saw according to claim 1, in which said plug-socket connecting means includes recess means provided on said driving unit and also includes an arm having one end adjustably connected to said handle means and having its other end provided with plug means adapted to engage and disengage said recess means.

8. A motor chain saw according to claim 7, which includes clamping means adjustably connecting said one end of said arm to said handle means.

9. A motor chain saw according to claim 1, in which said handle means has an approximately open O-contour with the end portions thereof located in a plane approximately parallel to the longitudinal extension of said crankshaft.

References Cited UNITED STATES PATENTS DONALD R. SCHRAN, Primary Examiner. 

1. A MOTOR CHAIN SAW, WHICH COMPRISES: A DRIVING UNIT INCLUDING A CRANK CASE AND A CRANK-SHAFT ROTATABLY MOUNTED IN SAID CRANK CASE AND A DRIVING PINION ROTATABLY CONNECTED TO SAID CRANK-SHAFT, GUIDING RAIL MEANS DETACHABLY CONNECTED TO SAID DRIVING UNIT, A SAW CHAIN GUIDED BY SAID GUIDING RAIL MEANS AND DRIVINGLY CONNECTED TO SAID SAID PINION, COVER MEANS DETACHABLY CONNECTED TO SAID DRIVING UNIT TO COVER SAID PINION TOWARD THE OUTSIDE OF SAID MOTOR CHAIN SAW, HANDLE MEANS HAVING TWO SPACED PORTIONS THEREOF FIRMLY CONNECTED TO SAID COVER MEANS, AND PLUG-SOCKET CONNECTING MEANS DETACHABLY CONNECTING SAID HANDLE MEANS TO SAID DRIVING UNIT THEREBY PERMITTING WITHDRAWAL OF SAID COVER MEANS AND SAID HANDLE MEANS TOGETHER AS A UNIT FROM SAID DRIVING UNIT. 